If the brain fundamentally needs sleep then we'd sleep regardless, just not aligned to the day-night cycle. There's quite a bit of variation in sleep patterns a

If the brain fundamentally needs sleep then we'd sleep regardless, just not aligned to the day-night cycle. There's quite a bit of variation in sleep patterns and amounts between different animals. Chinstrap Penguins only sleep a few seconds at a time, but still manage to rack up ~11hr sleep in a 24hr period! Elephants only sleep for ~2hr/day, horses for 3hr/day.